Investigation on cost-effective composites for CO2 adsorption from post-gasification residue and metal organic framework.

Cost-effective CO2 adsorbents are gaining increasing attention as viable solutions for mitigating climate change. In this study, composites were synthesized by electrochemically combining the post-gasification residue of Macadamia nut shell with copper benzene-1,3,5-tricarboxylate (CuBTC). Among the different composites synthesized, the ratio of 1:1 between biochar and CuBTC (B 1:1) demonstrated the highest CO2 adsorption capacity. Under controlled laboratory conditions (0°C, 1 bar, without the influence of ambient moisture or CO2 diffusion limitations), B 1:1 achieved a CO2 adsorption capacity of 9.8 mmol/g, while under industrial-like conditions (25°C, 1 bar, taking into account the impact of ambient moisture and CO2 diffusion limitations within a bed of adsorbent), it reached 6.2 mmol/g. These values surpassed those reported for various advanced CO2 adsorbents investigated in previous studies. The superior performance of the B 1:1 composite can be attributed to the optimization of the number of active sites, porosity, and the preservation of the full physical and chemical surface properties of both parent materials. Furthermore, the composite exhibited a notable CO2/N2 selectivity and improved stability under moisture conditions. These favorable characteristics make B 1:1 a promising candidate for industrial applications.

Plant-substrate biochar properties critical for mediating reductive debromination of 1,2-dibromoethane.

Dibromoethane is a widespread, persistent organic pollutant. Biochars are known mediators of reductive dehalogenation by layered FeII-FeIII hydroxides (green rust), which can reduce 1,2-dibromoethane to innocuous bromide and ethylene. However, the critical characteristics that determine mediator functionality are lesser known. Fifteen biochar substrates were pyrolyzed at 600 °C and 800 °C, characterized by elemental analysis, X-ray photo spectrometry C and N surface speciation, X-ray powder diffraction, specific surface area analysis, and tested for mediation of reductive debromination of 1,2-dibromoethane by a green rust reductant under anoxic conditions. A statistical analysis was performed to determine the biochar properties, critical for debromination kinetics and total debromination extent. It was shown that selected plant based biochars can mediate debromination of 1,2-dibromoethane, that the highest first order rate constant was 0.082/hr, and the highest debromination extent was 27% in reactivity experiments with 0.1 µmol (20 µmol/L) 1,2-dibromoethane, ≈ 22 mmol/L FeIIGR, and 0.12 g/L soybean meal biochar (7 days). Contents of Ni, Zn, N, and P, and the relative contribution of quinone surface functional groups were significantly (p < 0.05) positively correlated with 1,2-dibromoethane debromination, while adsorption, specific surface area, and the relative contribution of pyridinic N oxide surface groups were significantly negatively correlated with debromination.

Combined biochar and wheat-derived endophytic bacteria reduces cadmium uptake in wheat grains in a metal-polluted soil.

In this study, two wheat-derived cadmium (Cd)-immobilizing endophytic Pseudomonas paralactis M14 and Priestia megaterium R27 were evaluated for their effects on wheat tissue Cd uptake under hydroponic conditions. Then, the impacts of the biochar (BC), M14+R27 (MR), and BC+MR treatments on wheat Cd uptake and the mechanisms involved were investigated at the jointing, heading, and mature stages of wheat plants under field-plot conditions. A hydroponic experiment showed that the MR treatment significantly decreased the above-ground tissue Cd content compared with the M14 or R27 treatment. The BC+MR treatment reduced the grain Cd content by 51.5%-67.7% and Cd translocation factor at the mature stage of wheat plants and increased the organic matter-bound Cd content by 31%-75% in the rhizosphere soils compared with the BC or MR treatment. Compared with the BC or MR treatment, the relative abundances of the biomarkers associated with Gemmatimonas, Altererythrobacter, Gammaproteobacteria, Xanthomonadaceae, Phenylobacterium, and Nocardioides in the BC+MR-treated rhizosphere microbiome decreased and negatively correlated with the organic matter-bound Cd contents. In the BC+MR-treated root interior microbiome, the relative abundance of the biomarker belonging to Exiguobacterium increased and negatively correlated with the Cd translocation factor, while the relative abundance of the biomarker belonging to Pseudonocardiaceae decreased and positively correlated with the Cd translocation factor. Our findings suggested that the BC+MR treatment reduced Cd availability and Cd transfer through affecting the abundances of these specific biomarkers in the rhizosphere soil and root interior microbiomes, leading to decreased wheat grain Cd uptake in the contaminated soil.

Predicting the efficiency of arsenic immobilization in soils by biochar using machine learning.

Arsenic (As) pollution in soils is a pervasive environmental issue. Biochar immobilization offers a promising solution for addressing soil As contamination. The efficiency of biochar in immobilizing As in soils primarily hinges on the characteristics of both the soil and the biochar. However, the influence of a specific property on As immobilization varies among different studies, and the development and application of arsenic passivation materials based on biochar often rely on empirical knowledge. To enhance immobilization efficiency and reduce labor and time costs, a machine learning (ML) model was employed to predict As immobilization efficiency before biochar application. In this study, we collected a dataset comprising 182 data points on As immobilization efficiency from 17 publications to construct three ML models. The results demonstrated that the random forest (RF) model outperformed gradient boost regression tree and support vector regression models in predictive performance. Relative importance analysis and partial dependence plots based on the RF model were conducted to identify the most crucial factors influencing As immobilization. These findings highlighted the significant roles of biochar application time and biochar pH in As immobilization efficiency in soils. Furthermore, the study revealed that Fe-modified biochar exhibited a substantial improvement in As immobilization. These insights can facilitate targeted biochar property design and optimization of biochar application conditions to enhance As immobilization efficiency.

Efficient remediation of different concentrations of Cr-contaminated soils by nano zero-valent iron modified with carboxymethyl cellulose and biochar.

Nano zero-valent iron (nZVI) is widely used in soil remediation due to its high reactivity. However, the easy agglomeration, poor antioxidant ability and passivation layer of Fe-Cr coprecipitates of nZVI have limited its application scale in Cr-contaminated soil remediation, especially in high concentration of Cr-contaminated soil. Herein, we found that the carboxymethyl cellulose on nZVI particles could increase the zeta potential value of soil and change the phase of nZVI. Along with the presence of biochar, 97.0% and 96.6% Cr immobilization efficiency through CMC-nZVI/BC were respectively achieved in high and low concentrations of Cr-contaminated soils after 90-days remediation. In addition, the immobilization efficiency of Cr(VI) only decreased by 5.1% through CMC-nZVI/BC treatment after 10 weeks aging in air, attributing to the strong antioxidation ability. As for the surrounding Cr-contaminated groundwater, the Cr(VI) removal capacity of CMC-nZVI/BC was evaluated under different reaction conditions through column experiments and COMSOL Multiphysics. CMC-nZVI/BC could efficiently remove 85% of Cr(VI) in about 400 hr when the initial Cr(VI) concentration was 40 mg/L and the flow rate was 0.5 mL/min. This study demonstrates that uniformly dispersed CMC-nZVI/BC has an excellent remediation effect on different concentrations of Cr-contaminated soils.

Pristine/magnesium-loaded biochar and ZVI affect rice grain arsenic speciation and cadmium accumulation through different pathways in an alkaline paddy soil.

Cadmium (Cd) and arsenic (As) co-contamination has threatened rice production and food safety. It is challenging to mitigate Cd and As contamination in rice simultaneously due to their opposite geochemical behaviors. Mg-loaded biochar with outstanding adsorption capacity for As and Cd was used for the first time to remediate Cd/As contaminated paddy soils. In addition, the effect of zero-valent iron (ZVI) on grain As speciation accumulation in alkaline paddy soils was first investigated. The effect of rice straw biochar (SC), magnesium-loaded rice straw biochar (Mg/SC), and ZVI on concentrations of Cd and As speciation in soil porewater and their accumulation in rice tissues was investigated in a pot experiment. Addition of SC, Mg/SC and ZVI to soil reduced Cd concentrations in rice grain by 46.1%, 90.3% and 100%, and inorganic As (iAs) by 35.4%, 33.1% and 29.1%, respectively, and reduced Cd concentrations in porewater by 74.3%, 96.5% and 96.2%, respectively. Reductions of 51.6% and 87.7% in porewater iAs concentrations were observed with Mg/SC and ZVI amendments, but not with SC. Dimethylarsinic acid (DMA) concentrations in porewater and grain increased by a factor of 4.9 and 3.3, respectively, with ZVI amendment. The three amendments affected grain concentrations of iAs, DMA and Cd mainly by modulating their translocation within plant and the levels of As(III), silicon, dissolved organic carbon, iron or Cd in porewater. All three amendments (SC, Mg/SC and ZVI) have the potential to simultaneously mitigate Cd and iAs accumulation in rice grain, although the pathways are different.

Comprehensive evaluation of bioavailable phosphorus in biochar synthesized by co-pyrolysis of sewage sludge and straw ash.

The world's phosphorus (P) resources are gradually depleting. Sewage sludge is an important secondary P resource, and sludge-derived biochar for land use is an effective way to achieve P recovery. However, P in biochar synthesized by direct pyrolysis of sludge usually shows comparatively low bioavailability. In this study, biomass ash from different types of straw was used as an additive for co-pyrolysis with sludge. The distribution of different P fractions in the obtained co-pyrolyzed biochar was investigated. The P bioavailability of the co-pyrolyzed biochar was comprehensively evaluated by three methods, including chemical extraction, diffusive gradients in thin films (DGT) technology and pot experiments. The results indicate that the bioavailable P in co-pyrolyzed biochar is significantly positively correlated with the contents of K, Ca, and Mg elements in straw ash, which facilitate the transformation of P in sludge into forms that are more easily utilized by plants, including monetite (CaHPO4), hydroxyapatite (Ca5(PO4)3OH) and pyrocoproite (K2MgP2O7). Moreover, pot experiments show that the P contents in ryegrass shoots and roots cultivated in co-pyrolyzed biochar-added soils increased by 11.98-114.97 % and 28.90-69.70 %, respectively, compared to the control soil. The DGT technology could better reflect the uptake of P by plants with a Pearson correlation coefficient as high as 0.94. This study provides references for P resource recovery, and the collaborative reutilization of sewage sludge and straw ash.

Novel nanocomposite and biochar insights to boost rice growth and alleviation of Cd toxicity.

Cadmium (Cd) is an unessential and pervasive contaminant in agricultural soil, eventually affecting the food and instigating health issues. The implication of nanocomposites in agriculture attained significant attention to drive food security. Nanocomposites possess exceptional characteristics to stun the challenges of chemical fertilizers that can enhance plant yield and better nutrient bioavailability. Similarly, biochar has the ability to immobilize Cd in soil by reducing mobility and bioavailability. Rice husk biochar is produced at high temperature pyrolysis under anoxic conditions and a stable carbon-rich material is formed. To strive against this issue, rice plants were subjected to Cd (15, 20 mg kg- 1) stress and treated with alone/combined Ca + Mg (25 mg L- 1) nanocomposite and rice husk biochar. In our study, growth and yield traits showed the nurturing influence of Ca + Mg nanocomposite and biochar to improve rice defence mechanism by reducing Cd stress. Growth parameters root length 28%, shoot length 34%, root fresh weight 19%, shoot fresh weight 16%, root dry weight 9%, shoot dry weight 8%, number of tillers 32%, number of grains 20%, and spike length 17% were improved with combined application of Ca + Mg and biochar, with Cd (20 mg kg- 1), rivalled to alone biochar. Combined Ca + Mg and biochar application increased the SPAD 23%, total chlorophyll 26%, a 19%, b 18%, and carotenoids 15%, with Cd (20 mg kg- 1), rivalled to alone biochar. MDA 15%, H2O2 13%, and EL 10% were significantly regulated in shoots with combined Ca + Mg and biochar application with Cd (20 mg kg- 1) compared to alone biochar. POD 22%, SOD 17%, APX 18%, and CAT 9% were increased in shoots with combined Ca + Mg and biochar application with Cd (20 mg kg- 1) compared to alone biochar. Cd uptake in roots 13%, shoots 14%, and grains 21% were minimized under Cd (20 mg kg- 1) with combined Ca + Mg and B. pumilus application, compared to alone biochar. Subsequently, combined Ca + Mg and biochar application is a sustainable solution to boost crop production under Cd stress.

Influence of pyrolysis time on removal of heavy metals using biochar derived from macroalgal biomass (Oedogonium sp.).

In this study, pyrolysis was performed at different times to convert Oedogonium biomass into biochar. The physicochemical properties show that the pyrolysis time significantly impacts structural and morphological changes in biochar samples. The influence of pyrolysis time on the removal of multiple heavy metals was investigated. Owing to the presence of abundant functional groups, inorganic minerals and porous nature, biochar obtained from a 40 min pyrolysis time showed higher removal efficiency of heavy metals compared to biochars pyrolyzed at 20 mins and 60 mins even with higher concentrations of metal ions. The maximum adsorption capacity was observed 9.33, 10.74, 322.58, 13.70 and 9.11 mg/g with the biochar prepared at the pyrolysis time of 40 mins for Co, Ni, Cu, Zn and Cd, respectively. The adsorption isotherm is well fitted with the Langmuir adsorption model for heavy metals adsorption, and the kinetic study is well-defined by a pseudo second-order model.

Assessing biochar, clinoptilolite zeolite and zeo-char loaded nano-nitrogen for boosting growth performance and biochemical ingredients of peace lily (Spathiphyllum Wallisii) plant under water shortage.

BACKGROUND: Peace lily (Spathiphyllum wallisii Regel) is an ornamental indoor plant with promising cut flower market, as well as antiviral, pharmacological and ecological potentials. Water deficiency can have sound effects on the growth performance and aesthetic quality of such plant. The aim of this study was to investigate the consequences of zeolite, biochar, and zeo-char loaded nano-nitrogen application on the growth performance and biochemical components of peace lily under water shortage conditions. An experiment was conducted over two consecutive seasons (2021-2022) at the experimental nursery of Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, Giza, Egypt. Soil amendments; zeolite, biochar, and zeo-char loaded nano-nitrogen were prepared and applied to soil before cultivation. RESULTS: Our results revealed that the new combination treatment (zeo-char loaded nano-N) had an exceeding significant effect on most of the studied parameters. Vegetative traits such as plant height (35.7 and 35.9%), leaf number per plant (73.3 and 52.6%), leaf area (40.2 and 36.4%), stem diameter (28.7 and 27.1%), root number (100 and 43.5%) and length (105.7 and 101.9%) per plant, and fresh weight of leaves (23.2 and 21.6%) were significantly higher than control (commercially recommended dose of NPK) with the application of zeo-char loaded nano-N during the two growing seasons, respectively. Similar significant increments were obtained for some macro- (N, P, K, Mg, Ca) and micro- (Fe, Zn, Mn) elements with the same treatment relative to control. Chlorophyll (18.4%) and total carotenoids (82.9 and 32.6%), total carbohydrates (53.3 and 37.4%), phenolics (54.4 and 86.9%), flavonoids (31.7% and 41.8%) and tannins (69.2 and 50%), in addition to the phytohormone gibberellic acid (GA3) followed the same trend with the application of zeo-char loaded nano-N, increasing significantly over control. Leaf histological parameters and anatomical structure were enhanced with the new combination treatment in comparison with control. Antioxidant enzymes (catalase and peroxidase), proline and abscisic acid (ABA) exhibited significant declines with zeo-char loaded nano-N treatment relative to control. CONCLUSION: These findings suggest that incorporating soil amendments with nano- nutrients could provide a promising approach towards improving growth performance and quality of ornamental, medicinal and aromatic species under water deficiency conditions.

Sulfur-functionalized biochar: Synthesis, characterization, and utilization for contaminated soil and water remediation-a review.

The development of innovative, eco-friendly, and cost-effective adsorbents is crucial for addressing the widespread issue of organic and inorganic pollutants in soil and water. Recent advancements in sulfur reagents-based materials, such as FeS, MoS2, MnS, S0, CS2, Na2S, Na2S2O32-, H2S, S-nZVI, and sulfidated Fe0, have shown potential in enhancing the functional properties and elemental composition of biochar for pollutant removal. This review explores the synthesis and characterization of sulfur reagents/species functionalized biochar (S-biochar), focusing on factors like waste biomass attributes, pyrolysis conditions, reagent adjustments, and experimental parameters. S-biochar is enriched with unique sulfur functional groups (e.g., C-S, -C-S-C, C=S, thiophene, sulfone, sulfate, sulfide, sulfite, elemental S) and various active sites (Fe, Mn, Mo, C, OH, H), which significantly enhance its adsorption efficiency for both organic pollutants (e.g., dyes, antibiotics) and inorganic pollutants (e.g., metal and metalloid ions). The literature analysis reveals that the choice of feedstock, influenced by its lignocellulosic content and xylem structure, critically impacts the effectiveness of pollutant removal in soil and water. Pyrolysis parameters, including temperature (200-600 °C), duration (2-10 h), carbon-to-hydrogen (C:H) and oxygen-to-hydrogen (O:H) ratios in biochar, as well as the biochar-to-sulfur reagent modification ratio, play key roles in determining adsorption performance. Additionally, solution pH (2-8) and temperature (288, 298, and 308 K) affect the efficiency of pollutant removal, though optimal dosages for adsorbents remain inconsistent. The primary removal mechanisms involve physisorption and chemisorption, encompassing adsorption, reduction, degradation, surface complexation, ion exchange, electrostatic interactions, π-π interactions, and hydrogen bonding. This review highlights the need for further research to optimize synthesis protocols and to better understand the long-term stability and optimal dosage of S-biochar for practical environmental applications.

"Efficient novel fungal-enriched biochar formulation for hexavalent chromium bioremediation".

Chromium (Cr), a key element in industrial processes such as leather tanning, poses severe environmental hazards, particularly its hexavalent form, Cr(VI), which is highly toxic and prevalent in tannery effluents/sludge. The persistence and toxicity of Cr(VI) necessitate the development of effective remediation strategies to mitigate its environmental impact. This study investigated the potential of Trichoderma yunnanense (NBRICRF_97) and its combination with 0.5% sugarcane bagasse biochar (SBC) for the reduction of Cr(VI). The results demonstrated that T. yunnanense alone achieved a 91.04% reduction of 50 mg L-1 Cr(VI) within 72 h. Combined with 0.5% SBC, the reduction efficiency increased to 99.65% within 48 h. However, the efficiency decreased at higher concentrations (200 mg L-1). The combination also improved fungal growth and increased extracellular ChrR enzyme activity (13.07 U mg-1 protein compared to the control). Total glutathione activity was boosted by 161.07% at 100 mg L-1 Cr(VI). Antioxidant enzymes (SOD, POD, CAT) and proline mitigated oxidative stress and FTIR analysis revealed changes in fungal cell wall functional groups (-OH and -NH) upon Cr(VI) exposure. SEM-EDX confirmed chromium deposition on fungal surfaces. These results underscore the Cr(VI) detoxification capabilities of T. yunnanense and the synergistic benefits of SBC, suggesting a promising bioremediation strategy for Cr(VI)-contaminated environments. The integration of T. yunnanense with SBC offers a sustainable and cost-effective approach for the bioremediation of Cr(VI)-contaminated sites, with potential for implementation in large-scale environmental cleanup efforts.

Optimized pyrolytic synthesis and physicochemical characterization of date palm seed biochar: unveiling a sustainable adsorbent for environmental remediation applications.

This study focuses on the optimization and comprehensive characterization of biochar synthesized from date palm seeds (DPS), a prevalent agricultural waste in arid regions. Using response surface methodology (RSM) with a central composite design (CCD), we optimized the pyrolysis process by investigating the effects of time (1-3 h) and temperature (600-900 °C) on critical properties such as specific surface area, pore volume, and yield. The optimized biochar, produced at 828 °C for 1.7 h, demonstrated a high specific surface area of 654.8 m2/g and well-developed microporosity. Characterization techniques, including XRD, FTIR, SEM-EDS, and BET analyses, revealed an amorphous carbon structure with graphitic domains, diverse surface functionalities, and a heterogeneous porous microstructure. The biochar's point of zero charge at pH 7.58 indicates its potential for selective adsorption of charged contaminants. The close agreement between RSM-predicted and experimental values for specific surface area (652.1 m2/g vs. 654.8 m2/g) and micropore volume (0.191 cm3/g vs. 0.190 cm3/g) validates the effectiveness of the model in optimizing biochar properties. This research highlights the potential of DPS-derived biochar as a sustainable adsorbent for environmental remediation, opening avenues for valorizing agricultural wastes and contributing to circular economy principles.

Reclamation of co-pyrolyzed dredging sediment as soil cadmium and arsenic immobilization material: Immobilization efficiency, application safety, and underlying mechanisms.

The safe management of toxic metal-polluted dredging sediment (DS) is imperative owing to its potential secondary hazards. Herein, the co-pyrolysis product (DS@BC) of polluted DS was creatively applied to immobilize soil Cd and As to achieve DS resource utilization, and the efficiency, safety, and mechanism were investigated. The results revealed that the DS@BC was more effective at reducing soil Cd bioavailability than the DS was (58.9-73.2% vs. 21.8-27.4%), except for the dilution effect, whereas the opposite phenomenon occurred for soil As (25.5-35.7% vs. 35.7-42.8%). The DS@BC immobilization efficiency was dose-dependent for both Cd and As. Soil labile Cd and As were transformed to more stable fractions after DS@BC immobilization. DS@BC immobilization inhibited the transfer of soil Cd and As to Brassica chinensis L. and did not cause excessive accumulation of other toxic metals in the plants. The appropriate addition of the DS@BC (8%) sufficiently alleviated the oxidative stress response of the plants and enhanced their growth. These findings indicate that the DS@BC was safe and effective for soil Cd and As immobilization. DS@BC immobilization decreased the diversity and richness of the rhizosphere soil bacterial community because of the dilution effect. The DS@BC immobilized soil Cd and As via direct adsorption, and indirect increasing soil pH, and regulating the abundance of specific beneficial bacteria (e.g., Bacillus). Therefore, the use of co-pyrolyzed DS as a soil Cd and As immobilization material is a promising resource utilization method for DS. Notably, to verify the long-term effects and safety of DS@BC immobilization, field trials should be conducted to explore the effectiveness and risk of harmful metal release from DS@BC immobilization under real-world conditions.

Integration of Fe-MOF-laccase-magnetic biochar: From Rational Designing of a biocatalyst to aflatoxin B1 decontamination of peanut oil.

Enzymatic degradation of aflatoxins in food commodities has gained significant attention. However, enzyme denaturation in organic media discourages their direct use in oils to remove aflatoxins. For that, enzymes are immobilized or encapsulated for improved stability and reusability under unfavorable conditions. We sandwiched the laccase between a carrier and an outer protective layer. We used spent-mushroom-substrate (SMS) derived porous magnetic biochar as the laccase carrier and coated it with an iron MOF to create a biocomposite, Fe-BTC@Lac@FB. The immobilized laccase demonstrated enhanced chemical, thermal, and storage stability and proficient reusability. Fe-BTC@Lac@FB exhibited 11 times enhanced aflatoxin B1 (AFB1) degradation compared to free laccase (FL). In addition, thermally inactivated Fe-BTC@Lac@FB could adsorb 11.2 mg/g of AFB1 from peanut oil. Multi-aflatoxin removal also proved promising, while Fe-BTC@Lac@FB could retain > 85 % of AFB1 removal efficacy after five reusability cycles. Fe-BTC@Lac@FB treatment did not affect peanut oil quality as indicated by different oil quality parameters and proved essentially non-cytotoxic. All these aspects helped recognize Fe-BTC@Lac@FB as an excellent laccase-carrying material with exceptionally higher stability, activity, and reusability.

Adsorption of toxic metals from greywater using coconut husk biochar and spent green tea.

The discharge of wastewater into ground and surface waters can cause human and ecological health problems, hence eco-friendly, sustainable and cost-effective methods for removing toxic metals from wastewater are required. The study employed coconut husk biochar and spent impra ginseng flavoured green tea to adsorb cadmium (Cd), chromium (Cr) and lead (Pb) from greywater. The adsorption capacity of coconut husk biochar ranged from 88.70 % to 98.20 % for cadmium, 78 %-96 % for chromium and 95.71 %-99.29 % for lead whilst the spent impra ginseng flavoured green tea ranged from 94.03 % to 96.87 % for cadmium, 52 %-74 % for chromium and 98.52 %-99.48 % for lead. The maximum adsorption capacity (Qe) of coconut husk biochar ranged from 235.64 to 1132.40 mg/g for Cd, 1.31-8.80 mg/g for Cr and 58.85-415.80 mg/g for Pb. Lead demonstrated the highest affinity for the binding of coconut husk biochar and spent impra ginseng flavoured green tea adsorbent with a trend of Pb > Cd > Cr. Coconut husk biochar and spent impra ginseng flavoured green tea adsorbent were suitable for the toxic metals adsorption in the greywater. Cr showed different removal efficiencies where coconut husk biochar showed more effective removal than spent impra ginseng flavoured green tea. The application of coconut husk biochar and spent impra ginseng flavoured green tea in wastewater treatment is a green technology means and can lead to zero pollution of freshwater.

Biochar promotes compost humification by regulating bacterial and fungal communities.

Introduction: Humus can be formed during composting through biological pathways, nonetheless, the mechanisms through which bacterial and fungal communities govern the development of humus in compost with the addition of biochar remain uncertain. Methods: In this study, compost with cow dung and maize stover as feedstock was employed as a control group, and compost with 10% biochar added on top of the feedstock was adopted as a treatment group to investigate the effect of bacterial and fungal communities on humus formation during biochar composting. Results and Discussion: The results demonstrated that the humic acid content increased by 24.82 and 25.10% at the cooling and maturation stages, respectively, after adding biochar. Besides, the degree of polymerization content in the maturation stage was elevated by 90.98%, which accelerated the humification process of the compost. During the thermophilic and maturity stages, there was a respective increase of 51.34 and 31.40% in reducing sugar content, suggesting that the inclusion of biochar could furnish ample reducing sugar substrate for the Maillard reaction. The addition of biochar reduced the number of humus precursor-associated genera by 35, increased the number of genera involved in humus synthesis by two, and enhanced the stability of the cross-domain network between bacteria and fungi, which confirms that microorganisms contribute to the humification process by decreasing humus precursor consumption as well as increasing humus synthesis with the addition of biochar. Additionally, adding biochar could enhance the humification capacity of the compost pile by dominating the Maillard reaction with reducing sugars as the substrate and strengthening the function of humus synthesis-associated genera. This study enhances our comprehension of the regulatory pathways of biochar in the humification process during composting.

A new approach for endowing photocatalytic performance to biochar based on peryleneimide: Emphasizing the achievement of highly efficient degradation to RhB.

Having unique structural characteristics of biochar contributes great potential in photocatalysis, the preparation process complexity is still a great challenge for biochar-based photocatalysts. Based on this, this study proposes a new, simple, efficient, and flexible approach to preparing biochar-based photocatalysts by perylene diimide (GPC/PDI). The results showed that the hybridization between GPC and PDI was achieved by π-π stacking, which was reduced with increasing pyrolysis temperature, increased first and then decreased with increasing PDI content, and improved with enhanced solvent polarity. When the pyrolysis temperature was 400 °C, the PDI addition was 0.05 mg, and the reaction solvent was water, the degradation of 200 mg/L rhodamine B (RhB) by GPC400/PDI0.5 was 94%, and the reaction rate constant was 10 and 4 times higher than GPC400 and PDI, which were also effective in simulating actual wastewater treatment. This was attributed to the efficient electron-hole separation and migration along the π-π stacking direction due to the hybridization of GPC and PDI, which in turn reacts to produce reactive oxygen species (1O2, •O2-, •OH), facilitating the photocatalytic degradation process.

Pipe experiment elucidates biochar application depth affects nitrogen leaching under crop present condition.

Nitrogen leaching, resulting from the inefficient use of fertilizers, pollutes the environment, such as groundwater. Biochar can be applied to farmlands to mitigate nitrogen leaching. The effect depends on the application depth. However, the effect has not been examined under crop-farming conditions. Evaluating the interactions between biochar application depth and crop growth is indispensable for considering depth in the actual field. To address this, we conducted a pipe experiment with four treatments, no biochar (control), surface (0-5 cm), plow layer (0-30 cm), and subsurface (25-30 cm) applications, and compared the results with no-crop conditions from a previous study. Biochar application depth affected soil NO3--N and NH4+-N absorption ability and also influenced soil-water stress conditions, affecting crop growth. Surface biochar application improved nitrogen absorption and reduced soil-water stress, improving crop growth. The NO3--N leaching was reduced to 87.7%. Plow layer application worsened nitrogen absorption and resulted in frequent dry stress in the shallow-soil layer, preventing root growth in this layer. The NO3--N and NH4+-N leaching increased 106.4% and 264.1%, respectively. The effects of subsurface application were similar to those in the control. Selecting an appropriate application depth can simultaneously improve crop growth and reduce nitrogen leaching.

Synthesis of magnetic chitosan-composite biochar and its removal of copper ions (Cu2+) and methylene blue (MB) dye from aqueous solutions.

This study presents the synthesis and evaluation of a magnetic chitosan-modified biochar (M-BC-CS) composite, developed from waste maize straw, for the efficient removal of copper ions (Cu2+) and methylene blue (MB) dye from aqueous solutions. The composite was characterized using advanced techniques such as SEM, BET, FTIR, XPS, and XRD, confirming its enhanced surface area, porosity, and magnetic properties. The study is aimed at investigating the optimal conditions for adsorption of Cu2+ and MB by M-BC-CS through analysis of the influence of diverse adsorbent dosages, pH levels, reaction times, and initial solution concentrations. The findings demonstrated that the equilibrium duration for the adsorption of Cu2+ and MB by M-BC-CS was 60 min, resulting in corresponding equilibrium adsorption quantities of 54.42 mg/g and 67.23 mg/g, respectively. To elucidate the adsorption mechanism, the present investigation applied the pseudo-second-order kinetic model and the Langmuir isotherm. The outcomes suggested that the adsorption process is attributable to single molecular layer chemisorption. XPS and FTIR analysis determined that ion exchange and electrostatic interactions are the predominant mechanisms responsible for the simultaneous adsorption of Cu2+ and MB, and a competitive relationship exists between these mechanisms. In addition, M-BC-CS exhibited exceptional magnetic separation performance, enabling effortless and effective separation when exposed to an external magnetic field. Furthermore, the results demonstrated that M-BC-CS has good reusability and high adsorption capacity also in real wastewater, thus emphasizing its potential as a promising adsorbent for the elimination of Cu2+ and MB from aqueous solutions.